Government troops were reportedly preparing to assault the beleaguered Syrian town of Homs on Friday, after the regime blamed two deadly explosions in the northern city of Aleppo on 'terrorist gangs'.
Activists said civilians in Homs were "preparing to die" ahead of the assault, and added that medical supplies were in a desperate state.
Meanwhile international pressure to act and halt the violence continued to grow, even as China and Russia remained defiant in their refusal to condemn the Assad regime.
The Syrian state news agency reported Friday's explosions in the northern town killed 28 people and wounded 235 more.
It blamed the attacks on "armed terrorist gangs" and said children and soldiers were among the casualties.
Broadcasting extremely graphic pictures of human remains in the aftermath of the attacks, Sana said the blasts highlighted "the reality of events".
The rebel Free Syrian Army (FSA) said it was operating nearby, but denied responsibility for the attacks.
Captain Ammar al-Wawi, told Channel 4 News from Turkey that the regime was trying to "distract" the world from the situation in Homs.
"This explosion has two goals: drawing the attention and pretext for the army to enter Aleppo since the rallies have started there," he told Channel 4.
But Al Jazeera reported that a general in the FSA had admitted carrying out the bombings.
Aleppo, which is Syria's largest city, has not previously been the target of sustained violence by either opposition fighters or government forces.
However activists from the Local Coordination Committee said that demonstrations had taken place in Aleppo on Friday and that six people had been shot.
It was not possible for the Huffington Post to independently verify the claims.
Protests continued throughout the country, as shown by live video broadcast publicly online.
Meanwhile reports of up to 10,000 government troops massing on the edge of the beleaguered town of Homs also emerged, and the medical situation in the country continues to deteriorate.
The FSA, mostly holed up in the town where government rockets have pounded residential areas , is running low on ammunition and medical supplies and does not expect to be able to hold off President Assad's troops.
Sky News said that families were "preparing to die" ahead of an anticipated sweep of anti-government protesters.
Activists fear that troops will kill civilians "indiscriminately" once they retake the city.
The Local Co-ordination Committees, an activist network, said that 137 people were killed in Syria on Thursday, including 110 in Homs alone.
Up to 18 newborn babies died after power was cut to incubators at a local hospital, said the UK-based activist group Strategic Resource and Communication Centre.
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A report released by the Human Rights Watch (HRW) said that makeshift hospitals were "overflowing with the dead".
One resident of Homs told HRW: "I just came from the field hospital. There are three large rooms full of corpses. I’ve seen over 100 corpses today.
"Injured people are dying because we cannot treat them. There are still people in the street who are injured. They are missing body parts. We cannot pull them in because of the shooting. They will die in the street."
Mahmoud, another resident of Baba Amr, said:
"There is no bread, no medication and no nutritional supplies, and after a field hospital was targeted, we lost several of our medical staff."
Describing snipers in Homs picking off wounded civilians, he added: "Many of the wounded have very serious injuries – they lost their limbs, or eyes, had serious wounds to the body. They are in critical condition and are likely to die because there are no medical supplies to treat them properly."
The global protest network Avaaz has launched a $1m appeal for funds to support people in Syria with medical equipment.
Within hours of launching, over $100,000 had been raised, the group said.
Ricken Patel, executive director of Avaaz, said: "Russia and China have given Assad a licence to kill, and the Syrian people are at the darkest part of their night.
Avaaz says it has delivered more than $1.8m of medical equipment already and has smuggled almost two dozen correspondents into the country to report on the situation there.
It was reported by Bloomberg that the political risk monitors Eurasia Group sent a note to clients claiming "civil war" is imminent.
"Recent operations against activists and armed wings of the opposition are proving to be somewhat tactically successful," the note said, according to Bloomberg.
"At the same time, the intensity of clashes indicates that it would be very difficult to fully suppress the uprising. In the next few months, Syria will transition from civil conflict into civil war."
Speaking after meeting the Italian prime minister, Mario Monti, at the White House, American President Barack Obama said:
"We both have a great interest in ending the outrageous bloodshed that we've seen, and see a transition from the current government that has been assaulting its people."
Commentators said that the Syria rebels would not be able to succeed without intervention.
Hassan Mneimneh, a senior transatlantic fellow with the German Marshall Fund in Washington, wrote that:
"The Syrian revolutionaries have broken through the wall of fear. Their ultimate success depends on denying the regime the ability to re-erect it. They will not be able to succeed without western help."
At least 400 people have died in Syria in a week of intense violence.
The United Nations says close to 6,000 people have died in the country since the start of anti-government protests in March 2011.Suggest a correction